1. Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method and apparatus for detecting a heterogeneous communication system on the basis of a silent duration evaluation in a wireless communication system.
2. Related Art
An industrial, scientific and medical (ISU) band used for industrial, scientific, and medical purposes, rather than for a communication purpose, a band (e.g., a TV band) employing a cognitive ratio (CR) technique, and the like, are open spectrum bands communication devices using different protocols share to use. Various communication devices operating in the open spectrum band may need to detect whether or not different types of communication devices operate, as well as to detect whether or not the same type of communication devices as that of the communication devices operate. Namely, each of the communication devices must detect whether or not the same type of communication devices operate and whether or not communication devices belonging to different types of communication systems operate to determine whether or not communication has started and communication quality. Thus, in order to detect a heterogeneous communication system, a proper detection apparatus for detecting a signal strength and a spectrum pattern, or the like, is required.
Recently, as communication devices using the open spectrum band increase, a coexistence technique allowing heterogeneous communication system using the open spectrum band to coexist is required. Also, in order to apply the coexistence technique, heterogeneous communication systems operating in the open spectrum band must be first detected. In this case, however, whether or not heterogeneous communication systems exist may be determined through an energy detection method of determining the presence or absence of a transmitted signal, but it is difficult to determine what kind of types the heterogeneous communication systems are. In addition, the determining of the types of heterogeneous systems requires an algorithm for capturing a relatively complicated signal and determining the type of the signal, increasing the system complexity.
Thus, generally, without a coexistence technique, communication devices operating in the open spectrum band operate such that, when communication quality is degraded, they move to a different band. Alternatively, in order to determine types of heterogeneous communication systems, a somewhat complicated algorithm, such as capturing a signal for a certain period and cyclo-stationary-detect it by using a fast Fourier transform (FFT), and the like, has been used.
Therefore, a method for easily and effectively detecting types of heterogeneous communication systems is required.